package com.yang.app;

import java.io.IOException;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapred.MapReduceBase;
/**
 *
 */
public class MaxTemperatureMapper 
	extends MapReduceBase implements Mapper<LongWritable,Text,Text,IntWritable>{

	private static final int MISSING = 9999;
	
	@Override
	public void map(LongWritable key, Text value, Context context)
		throws IOException{
		String line = value.toString();
		String year = line.substring(15,19);
		int airTemperature;
		if(line.charAt(87) == '+'){
				//parseInt doesn't like leading plus signs
			airTemperature = Integer.parseInt(line.substring(88,92));
		}else{
			airTemperature = Integer.parseInt(line.substring(87,92));
		}
		String quality = line.substring(92,93);
		if(airTemperature != MISSING && quality.matches("[01459]")){
				context.wirte(new Text(year), new IntWritable(airTemperature));
		}
	}
    //public static void main( String[] args )
    //{
    //    System.out.println( "Hello World!" );
    //}
}
